Wave front indicator



im o. SPRQULE Filed Nov. 26, 1938 4 Smets-Sheet 1 fida' E.

INVENTQ@ QZ. p, Q, SPROULE EQ WAVE FRONT INDICATORS Filed Nov. 2s, 1938 f. sheets-sheet 2 ci time I" in mdimm l it Urli miomie, London, fewest to mth imeph Hur el; in m mgl omeil 1v N to Mener nach@ n @on Limited., london, minnd, a weithin ilmited-iiahnitr eomnnny ltpplimnon November tt, l in @emit mitnin N "lhic invention relatw to lmprovemente in wave iront indicatore and has for ite prlncipel object to provide means whereby the direction oi travel ci a wave front can be determined more rapidly, with leso disturbance from interference and with nix-eater accuracy than has been possible hitherto e.; im as it provides for e direct reading oi the direction of travel oi' a compressionai wave.

Another object oi the invention is to provide means more responsive to eounds which are erceedingly varieblek in. intensity and/or mundo oi infrequent occurrence and/or eounds at tu. intervalo of time, than mown anpaiaiuni mich ier example as blnaurai directional eretemc or the directional hydrophone.

lt it irnown that the direction of travel oi' a wmpreesional weve may be determined by meas- 1 the time interval between the arrivel of the same wave pulse at dierent receivers, preter- Liu nu ably disposed in, line and various arrangementsr oi oecilioeraphs, and other time measuring devices have been employed for thin purpose, but due to the necessity for interfering with the reoordine process in order to tate readings, or for manual adjustment in order to eecure n null ponition or a binaural croce over it hm not 1u possible to tane euizetantlally continuent reedinee oi direction without lone oi time.

The invention alec contemplant@ the conetitution oi an instnimentwhlch me. he applied to the record at any moment in n minnie, direct and edectlve manner without mterierine with (im. lit-352) the production oi the raid record to that in prac- Y tice a number oi tuccmive l l- M t caubetaheneocioselyapacedonatimehm that in enect a continuent readline of direction is available.

The invention constats in a wave iront indicator comprising two or more receivers, Wneive to eompreseionai waves and adapted to traneiorni auch waves into electrical pulses, arranged on e. hace line in deinite reletlon with one another; two or more indicators, responsive to electrical pulses, electrically connected respectively to eaid receivers, and is cheracterired in tiret euch indicatore are located in corresponding relative petitions ae the receivers ond that meow wave iront to the receiver heee line to he direct- W nceertained from the originar relation ol the indicated pule without interrupting the operation oi the indication producine elemente.

it will he understood that the bose line reierred to above need not be straight nor regularly curved so that the recelvere can he located in any arbitrarily selected positions; that any number oi receivers, more than one, and associated indicators may be used within practical limits; and that the contrivances referred to ae indicators may be cathode ray or other apparatus giving a visual result or an electrochemical or other recorder giving a graphic result.

--In the drawings: A

Figure l shows a schematic errangment ol the invention with two receivers;

Figure i is a diagram showing the relation ci two receivers and the direction of travel o! a wave;

Figure 3 le a diarem showing the geometrical nnelvsis of the record produced by the arrangement of New@ 3;

Fieure i is o iront elevation of one form of chart reader suitable for use with this invention when the recorder has o. continuously rotatine arm with two tyli thereon;

Pleure o ie a iront elevation of another form of chart rwder;

rieure t shows the form of chart or indication obtained when the paths are straight parallel linee and also shows the method of analysis;

c Figure 'l ir n iront elevation oi' a simple form of chart reader suitable for use with the form oi chart chown in, Figure 6;

K Figure d is a'front elevation of a modified form ci chart reader suitable for use with the form of eliart shown in Figure o;

` Pleure 9 is a front elevation ci another kind oi chart reader;

Figure l0 is a side elevation oi Figure 9;

Figure 1l shows a schematic arrangement of the invention with three receivers;

Figure-12 shows a chart when four receivers are urged:

more 18 shows an arrangement in which cathode ray oscillograph are used;

Figures li and l5 show the @werent kinde ci indications obeerved in the comi-renewing; mirror.

In the iollowine deecription the invention it emlained or way of example only with reference to round waves.

Fitrure l shows a very rimple arrangement compricing two sound wave receivers R1 and R1, amplierc h1 and A* and an electrochemical recorder E having an arm rotating about an arie O and carrying two styli S1 and S2 followine parallel paths t, t and having the line a joinlng the points S S of contact of the styli Sl and S2 

